Jack



Feb. 5, 1929.

L. G. sHOoK JACK 2 Sheets-Sheet 1 Filed 0G17.l l. 1927 faken-01'Zu/fence G SOQ Feb. 5, 1929.A 1,701,314

' L. G. SHOCK JACK Filed oct. 1, 1927 sheets-'sheet 2 Patented 1929,.-UNITED STATES.

'PATENTJoFI-TICE.

- 1,1oi,311 4f LAWRENCE G. SHOCK',l OF LOS ANGELES, CALIFORNIA..

JACK.

' Apuoaaon nie october 1, 1927. serial im. 223,334.

ing or rotating the screw,y the rotation of v at the Sametime swingingythe ends connect-- l ed to the base and to the head upwardly and lifted;

the screw actuating two pairs of arms somewhat on the toggle princ-ipleso that when an axle of the car is engage it may be readily A particularobject o'f my invention is the arrangement forinterconnecting thetoggle` arms to the screw so that as the arms are drawn inwardly oroutwardly along the screw they also act to swing in an upward ondownward direction.

Another feature of my invention is the interconnecting of thetogglefarms with the screw to cause the ends connected to the screw tobe drawn to and over each other and also downwardly, as well as hav/fingthe ends connected to the base and the/headinterconnect-V ed by Vteethsegments. I prefer to perform the interconnection between the ends ofthe toggle arms by means of geared segments or the equivalent.

Infon'e construction I utilize a pai of nuts on each end of theoperating'screw, these nuts being held from rotation and havin rackteeth on opposite edges. These rac teeth engage teeth on the segments ofthe toggle arms at their outer ends thus causing theV arms tov swing asthe nuts are drawn towards the center ofthe screw or forced outwardly.In ,another construction the segments on the outer,` ends of the togglearms areiformed with a' worml type of gear which engages directly withthe thread on the screw, such segments, therefore, j functioning as anut, causing the outer ends of the toggle arms'to travel in thedirection in which the screws are operating and also the worm andl gearconnection regulates the angular turning of the toggle arms.

It is well known that inthe toggle. ty e 'of operated lifting jacks whent ejac s are in? their lowered position in which the arms are at a smallangle to the screw it re uires a' large amount of power to lift. the

weight being elevated and it is ver often dilfi'cult to start such jacksin lifting the weight. When, however, the toggle. arms 'of drawings, in,which:

approach each other' in a vertical direction and are at a small angle tothe vertical it is 5 Acomparatively easy to actuate thejacks. A

characteristic of my jack is the feature lof a. torque or angular turnbeing'imparted to the 'toggle arms throughout their whole movement, thisvbeing especially 'effective when the jack i's in its lowered positionto raise a weight. The positive turning force given to the armsCfacilitates the opening of' the jack and is an especially valuablefeature paratively small.

understood from the following description Figure l is a plan view of onetypeof jack,

Fig. 2 is a side elevation't'akenin the direction of the, arrow 2 ofFigure 1, partly broken away Fig. 3 is a detailed-vertical sectionthrough the base on the line 3%.-3 of Figure 2,

Fig. 4 is a detailed vertical section on the line 1 -4 of Figure arrows,

Fig. 5 is a horizontal view ofl a modified form of jack,

Fig. 6 is a slde elevation taken inthe direc-r tion of the arrow 6 ofFigure 5 partly broken away, and

Fig. 7 is a'vertical section taken upon the line 7-7 upon Fig. 6. t uThe form of jack illustrated in Figures 1 to 4 is substantially asfollows:

The base 1 has a pair of upstanding t flanges 2 with a. pair yof pivotpins 3 extending therethrough. Each of the toggle arms are pivoted toone of` the pivot pins and both have' geared segments 4 'intermeshingTheinner ends of the toggle arms, that is, the ends' connected to thebase andthe head are'actuated simultaneously due to the intermeshingteeth 4. Each of the toggle arms is made substantially similar and hassidebars 5, on the pivots 3 being spaced by sleeve 6. i At the outerends blocks 7 are secured to the bars 5 by rivets 8 or the like. Thehead 9 is preferably channel shaped having the pivot pins 10 extendingthrough theiianges 11 with the'sleeve 6 separating the ends somewhat asin regard to the base.

. The upper toggle arms are designated generally by` the numeral 12 andthe lower toggle arms generally by the numeral 13. The

blocks 7 of each of these arms have a toothed 2 in the direction ofthe lwhere the clearance between the `ground and the bottom of the article tobe lifted is com.

segment 14 and at the axial vcenter of the segment arev pivot pins 15between which the strap links 16 are connected., These' strap links areon the opposite sides of the arms and se ments.

he operating screw 17 is reversely threaded and has nuts 18 threadedthereon, these y nuts being attened on the sides 19 next the `straps16and have rack teeth 20 thereon 'are forced to part, that is, the headis separated from the base. The inward movement of the nuts also swingsthe arms, due to the engagement of the rack teeth on the nuts with theteeth on the se ments 14. rlhis action forces the inner en s ofthe upperarms upwardly and the inner ends oft-he lower arms downwardly relativeto the screw.

In lowering the jack the operation is substantially the' reverse of thatabove set forth, it being necessary to rotate the screw as the weight ofthe vehicle cannot depressthe jack even when the arms are considerablyfiattened out relative to the screw. It is to be noted in theconstruction above described that the straps 16 .are not connected tothe nuts but .are pivotally connected to the toggle arms atl the axialcenter of the toothed segment in-mesh with the threads of the screw.

The., construction of the jack of Figures 5, 6 and 7, is substantiallyas follows in so far as it diifers from that of Figures 1, 3 and 4:thelower and upper toggle arms 25 and 26 are each formed of two sidebars whichV e'xtend from the intermeshing teeth 4 to the curvedsegmental ends 27. These ends-are positione to` contact as indicated bythe numeral 28, such ends being held by straps 16, having pivot bars 15,as inthe former construction. -Blocks 29' are secured' by rivets `30pvto the side bars of the lower and@ upper togglearms. These blocks haveworm A gear teeth 31 to mesh with the threads ofthe screw 17.

fthe operation of the jackof Figures 5,

y v 6 and 7 assuming the `same is in a lowered.

position asshown` in Figure 6, on rotation ofthe screw in the .properdirection the inl termeshing of theA threads of the screw` and the wormthreadsl of the segments cause the outer-ends of the'toggle arms to bedrawn inwardly and jat the same time the head and base are pressedapart. Theinner ends of the armsl have osclllating or swin ing moontheinner ends of the arms cause these'to move simultaneously through thesame are. lin the action of the lifting jack, when.V there is a heavyweight on the gael;` thepressure is transmitted between the rollingsegments 27,

which, asy above described, have a co tact point at 28,y thus there isnov heavyl t rust placed on the screw 'or the worm geared teeth 31. Inthe reverse operation the weight of the vehicle cannot lower the jaclron account of the worm and'gear operation and' even when the toggle armsare 1n a position with slight angularity to the screw, the heavy weightof the vehicle cannot force the head and base together but requirescontinuous operation of the crew to lower the jack.

It will be noted that a characteristic feaplied to the screw ll amenabled to lift heavier I weights when the jack is nearly in a collapsedposltion than with the yordinary type of screw thread and toggle armtype of ack.

Another feature to be note my invention is that the length of the leverarm provided by the segments on the ends of in regard to ture of myinvention is the segmental gears l on the outer ends of the toggle arms,theseY the'toggle arms connected tothe nuts or di- 4 rectly tothe screwmay be chan ed in relation-to the length of such arms etween the pivotalconnection to the links and the pivotal connection to the head or base.Such changewill chan e the leverage with which the. toggle arms unctionin relation to the head and the base in spreading the same apart.

Ify a certain definite lift for the jack is required and, the head andbase being of substantiall constant size, if the segments are increasedin radius,-the length of the toggle ar/ms from theaxial center of thesegments to their pivotal connection to the' head and base' may beshortened.

It' will be understood that various chan es i ma be made in the detailsof the construction wit outdeparting from the spirit and scope of theinvention as deinedfbythe appended claims.

' I clalm:

v 1. A jack comprising a combination, 'a plu-` ralty'y of togglel arms,the inner ends bein connected to a base and a head, a screwan a groovedsegmententhe louter end of thev arms, and means forming-an operativegeared ist connection between the segments andthe tion. I'In' vthis`case the, intermeshing teeth 2.,Ajack comprising-abombination,apl- )i0rality 'of toggle arms', the inner being ends of the arms.

connected to a base and a head, a screw, a' plurality of nuts on thescrew and a'gear'ed connection between the nuts and the outer 3. vA jackcomprising a combination, a plurality of toggle arms, the -innerendsrbeing connected to abase and a head, a screw, a

,plurality of nuts on the screw, means rescrew, links pivotallyconnecting the outer ends of the upper and lowerpalr of toggle armsl anda. .geared connection between the outer ends of said arms and the nuts.

A jackas claimed in claim 4, links en-` gaging the nuts and preventingthe rotation of same, said nuts having rack teeth and the outer ends ofthe toggle arms having segments l.

with teeth meshing with said racks.

6. A jack comprising in co'mbinatiom'a-n]I upper and lower pair oftoggle arms, the in# ner ends of said arms being pivotally connected toa head and a base res ectively,in termeshing geared teeth on the mnerends of 5 said arms, a screw havingl reverse threads, a

pair of nuts having racks on their upper and ow'er edges, segmentshaving :geared teeth on the outer ends o f. the arms, said geared teethmeshing with the racks, and links pivotally connected to the outer endsof the arms.

7. A jack comprising a base, a head, an upper air of arms having theirinner ends pivotal y connected to the head` a lower pair of arms havingtheir inner ends pivotally connected to the base, means pivotallyconnected to the outer ends of correspondingr arms of the pairsand-,connecting them to each other, the pivots at the outer ends of thearms constituting fulcrums, there being teeth formed on the 'outer endsof the arms, and means engageable upon the teeth for drawing the outerends of the arms inwardly.

In testimony'whereof I have signed my name to this specification. 1.

. LAWRENCE G. s HooK.

